Answer: Pandas groupby cumulative sum

#pandas #cumsum #resetindex

answer re: Pandas groupby cumulative sum

Mar 26 '14

This should do it, need groupby() twice:

df.groupby(['name', 'day']).sum() \
  .groupby(level=0).cumsum().reset_index()

Explanation:

print(df)
   name        day   no
0  Jack     Monday   10
1  Jack    Tuesday   20
2  Jack    Tuesday   10
3  Jack  Wednesday   50
4  Jill     Monday   40
5  Jill  Wednesday  110

# sum per name/day
print( df.groupby(['name', 'day']).sum() )
                 no
name

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